Python Array

class Array(object):

    def __init__(self, length = 0, baseIndex = 0):
        assert length >= 0
        self._data = [ None for i in xrange(length) ]
        self._baseIndex = baseIndex
    def __copy__(self):
        result = Array(len(self._data))
        for i, datum in enumerate(self._data):
            result._data[i] = datum
        result._baseIndex = self._baseIndex
        return result
    def getOffset(self, index):
        offset = index - self._baseIndex
        if offset < 0 or offset >= len(self._data):
            raise IndexError
        return offset

    def __getitem__(self, index):
        return self._data[self.getOffset(index)]

    def __setitem__(self, index, value):
        self._data[self.getOffset(index)] = value
    def getData(self):
        return self._data

    data = property(
        fget = lambda self: self.getData())

    def getBaseIndex(self):
        return self._baseIndex

    def setBaseIndex(self, baseIndex):
        self._baseIndex = baseIndex

    baseIndex = property(
        fget = lambda self: self.getBaseIndex(),
        fset = lambda self, value: self.setBaseIndex(value))

    def __len__(self):
        return len(self._data)

    def setLength(self, value):
        if len(self._data) != value:
            newData = [ None for i in xrange(value) ]
            m = min(len(self._data), value)
            for i in xrange(m):
                newData[i] = self._data[i]
            self._data = newData

    length = property(
        fget = lambda self: self.__len__(),
        fset = lambda self, value: self.setLength(value))